According to the National Association of Home Builders, the nationwide housing affordability during the fourth quarter of last year rose to its highest level in the 20 years that it has been measured.

The finding was a joint NAHB/Wells Fargo Housing Opportunity Index (HOI) study and it indicated that 73.9 percent of all new and existing homes sold in the fourth quarter of 2010 were affordable to families earning the national median income of $64,500. The previous record was set in the fourth quarter of 2009 at 72.5 percent.

The most affordable major housing market in the country for a second consecutive quarter was Indianapolis-Carmel, Indiana. In that state, 93.5 percent of all homes sold were affordable to households earning the area's median family income of $68,700.

What does this all mean? Now remains a good time to buy, unless you are looking to do so in Santa Cruz, which is the least affordable small metro housing market in the country.